Programming tips for ParaDiS

This page is intended to developers of the ParaDiS code. We share a few programming tips we discover in ParaDiS.

The Peach-Koehler force exerted on a dislocation line element $ξ$ with Burgers vector b by a stress $σ$ is given by $F = (\sigma \cdot b) \times \xi$

The way this force is implemented in ParaDiS is as follows (see ComputeSegSigbRem in NodeForce.c). Consider two neighboring nodes Node 1 and Node 2. We want to compute the force on each of these nodes. Suppose these nodes have coordinates $x 1$ and $x 2$ respectively.

1. The dot product $\sigma \cdot b_1$ is computed for each ordered pair (Node 1, Node 2). Each node gets the same $\sigma \cdot b_1$ , where here $b 1$ is the Burgers vector of Node 1. Note that nodes are ordered in ParaDiS and only the pair (Node 1, Node 2) is considered and not (Node 2, Node 1) in this case.

2. This dot product is then use to calculate the Peach-Koehler force. Node 1 gets the force $F_1 = \frac{1}{2} \sigma \cdot b_1 \times (x_2 - x_1)$ and Node 2 gets the force $F_2 = \frac{1}{2} \sigma \cdot b_1 \times (x_2 - x_1)$ .